Citigroup, the largest U.S. bank, said it will rebrand itself as "Citi" and sell its trademark red umbrella to St. Paul Travelers.

New York-based Citigroup said it will do business as Citi, but its legal name will remain Citigroup.

Citi "is how most of our clients think about us already," Chief Executive Charles Prince said in a statement. "Through a unified brand, we will leverage this symbol."

Citigroup said the sale of the umbrella required antitrust approval and was scheduled to close in March. St. Paul said it will thereafter change its name to Travelers Cos., and change its ticker symbol to "TRV."

Beginning in the second quarter, Citigroup's investment bank, private bank, research unit and alternative investments unit will carry the Citi name, and the brokerage will be known as Citi Smith Barney. There are no plans to change the Banamex brand in Mexico, Citigroup said.

The change marks Prince's latest step away from the banking model of Sanford "Sandy" Weill, his predecessor and mentor, who came up with the Citigroup name.

Citigroup joins companies such as Apple, formerly Apple Computer; and disability insurer UnumProvident, which is becoming Unum Group, to announce name changes this year. Other companies to shorten names in recent years include Dell and FedEx.

The name and umbrella being discarded were the brainchild of Weill, who said he sought "balance" between Citicorp and his Travelers Group when those companies merged in 1998 to form Citigroup. Travelers first used the umbrella in 1870.